view release on metacpan or  search on metacpan

7zip/C/LzmaDec.c  view on Meta::CPAN

#define kNumPosBitsMax 4
#define kNumPosStatesMax (1 << kNumPosBitsMax)

#define kLenNumLowBits 3
#define kLenNumLowSymbols (1 << kLenNumLowBits)
#define kLenNumMidBits 3
#define kLenNumMidSymbols (1 << kLenNumMidBits)
#define kLenNumHighBits 8
#define kLenNumHighSymbols (1 << kLenNumHighBits)

#define LenChoice 0
#define LenChoice2 (LenChoice + 1)
#define LenLow (LenChoice2 + 1)
#define LenMid (LenLow + (kNumPosStatesMax << kLenNumLowBits))
#define LenHigh (LenMid + (kNumPosStatesMax << kLenNumMidBits))
#define kNumLenProbs (LenHigh + kLenNumHighSymbols)


#define kNumStates 12
#define kNumLitStates 7

#define kStartPosModelIndex 4
#define kEndPosModelIndex 14
#define kNumFullDistances (1 << (kEndPosModelIndex >> 1))

#define kNumPosSlotBits 6
#define kNumLenToPosStates 4

#define kNumAlignBits 4
#define kAlignTableSize (1 << kNumAlignBits)

#define kMatchMinLen 2
#define kMatchSpecLenStart (kMatchMinLen + kLenNumLowSymbols + kLenNumMidSymbols + kLenNumHighSymbols)

#define IsMatch 0
#define IsRep (IsMatch + (kNumStates << kNumPosBitsMax))
#define IsRepG0 (IsRep + kNumStates)
#define IsRepG1 (IsRepG0 + kNumStates)
#define IsRepG2 (IsRepG1 + kNumStates)
#define IsRep0Long (IsRepG2 + kNumStates)
#define PosSlot (IsRep0Long + (kNumStates << kNumPosBitsMax))
#define SpecPos (PosSlot + (kNumLenToPosStates << kNumPosSlotBits))
#define Align (SpecPos + kNumFullDistances - kEndPosModelIndex)
#define LenCoder (Align + kAlignTableSize)
#define RepLenCoder (LenCoder + kNumLenProbs)
#define Literal (RepLenCoder + kNumLenProbs)

#define LZMA_BASE_SIZE 1846
#define LZMA_LIT_SIZE 768

#define LzmaProps_GetNumProbs(p) ((UInt32)LZMA_BASE_SIZE + (LZMA_LIT_SIZE << ((p)->lc + (p)->lp)))

#if Literal != LZMA_BASE_SIZE
StopCompilingDueBUG
#endif

#define LZMA_DIC_MIN (1 << 12)

/* First LZMA-symbol is always decoded.
And it decodes new LZMA-symbols while (buf < bufLimit), but "buf" is without last normalization
Out:
  Result:
    SZ_OK - OK
    SZ_ERROR_DATA - Error
  p->remainLen:
    < kMatchSpecLenStart : normal remain
    = kMatchSpecLenStart : finished
    = kMatchSpecLenStart + 1 : Flush marker
    = kMatchSpecLenStart + 2 : State Init Marker
*/

static int MY_FAST_CALL LzmaDec_DecodeReal(CLzmaDec *p, SizeT limit, const Byte *bufLimit)
{
  CLzmaProb *probs = p->probs;

  unsigned state = p->state;
  UInt32 rep0 = p->reps[0], rep1 = p->reps[1], rep2 = p->reps[2], rep3 = p->reps[3];
  unsigned pbMask = ((unsigned)1 << (p->prop.pb)) - 1;
  unsigned lpMask = ((unsigned)1 << (p->prop.lp)) - 1;
  unsigned lc = p->prop.lc;

  Byte *dic = p->dic;
  SizeT dicBufSize = p->dicBufSize;
  SizeT dicPos = p->dicPos;
  
  UInt32 processedPos = p->processedPos;
  UInt32 checkDicSize = p->checkDicSize;
  unsigned len = 0;

  const Byte *buf = p->buf;
  UInt32 range = p->range;
  UInt32 code = p->code;

  do
  {
    CLzmaProb *prob;
    UInt32 bound;
    unsigned ttt;
    unsigned posState = processedPos & pbMask;

    prob = probs + IsMatch + (state << kNumPosBitsMax) + posState;
    IF_BIT_0(prob)
    {
      unsigned symbol;
      UPDATE_0(prob);
      prob = probs + Literal;
      if (checkDicSize != 0 || processedPos != 0)
        prob += (LZMA_LIT_SIZE * (((processedPos & lpMask) << lc) +
        (dic[(dicPos == 0 ? dicBufSize : dicPos) - 1] >> (8 - lc))));

      if (state < kNumLitStates)
      {
        state -= (state < 4) ? state : 3;
        symbol = 1;
        do { GET_BIT(prob + symbol, symbol) } while (symbol < 0x100);
      }
      else
      {
        unsigned matchByte = p->dic[(dicPos - rep0) + ((dicPos < rep0) ? dicBufSize : 0)];